Everybody's poopin......

Most all 18 of my hens have the poops!!! I'm kind of concerned because it seems pretty bad. I'm trying to figure out why. I feed them sunflower seeds once in a while for a treat. The other night I bought a new bag. That seems to be when it started. But I also started using another waterer. My 5 gallon one kept leaking. So I replaced it with two smaller ones, one of which I put outside. It was empty in seemingly no time. The big one was in the coop and they never seemed to drink a lot. Just made me wonder if their bodies weren't used to having all the water.